Condensed Consolidating Statements of Cash Flows (Details) - USD ($) $ in Millions	6 Months Ended
Nov. 30, 2019	Nov. 30, 2018
Condensed Cash Flow Statements Captions [Line Items]
CASH PROVIDED BY (USED IN) OPERATING ACTIVITIES	$ 2,074	$ 2,179
INVESTING ACTIVITIES
Capital expenditures	(3,266)	(2,634)
Proceeds from asset dispositions and other	4	53
Cash used in investing activities	(3,262)	(2,581)
FINANCING ACTIVITIES
Proceeds from short-term borrowings, net	150	248
Proceeds from debt issuances	2,093	1,233
Principal payments on debt	(1,021)	(785)
Proceeds from stock issuances	26	45
Dividends paid	(339)	(173)
Purchase of treasury stock	(3)	(1,271)
Other, net	(5)	1
Cash provided by (used in) financing activities	901	(702)
Effect of exchange rate changes on cash	(1)	(38)
Net decrease in cash and cash equivalents	(288)	(1,142)
Cash and cash equivalents at beginning of period	2,319	3,265
Cash and cash equivalents at end of period	2,031	2,123
Consolidation Eliminations [Member]
Condensed Cash Flow Statements Captions [Line Items]
CASH PROVIDED BY (USED IN) OPERATING ACTIVITIES	37	(47)
FINANCING ACTIVITIES
Net decrease in cash and cash equivalents	37	(47)
Cash and cash equivalents at beginning of period	(46)	(15)
Cash and cash equivalents at end of period	(9)	(62)
Parent Company [Member] \| Reportable Legal Entities [Member]
Condensed Cash Flow Statements Captions [Line Items]
CASH PROVIDED BY (USED IN) OPERATING ACTIVITIES	(1,759)	262
INVESTING ACTIVITIES
Capital expenditures	(2)	(2)
Proceeds from asset dispositions and other	(12)	(45)
Cash used in investing activities	(14)	(47)
FINANCING ACTIVITIES
Proceeds from short-term borrowings, net	150	248
Net transfers from (to) Parent	700	(344)
Payment on loan between subsidiaries	(326)
Proceeds from debt issuances	2,093	1,233
Principal payments on debt	(956)	(750)
Proceeds from stock issuances	26	45
Dividends paid	(339)	(173)
Purchase of treasury stock	(3)	(1,271)
Other, net	(4)
Cash provided by (used in) financing activities	1,341	(1,012)
Net decrease in cash and cash equivalents	(432)	(797)
Cash and cash equivalents at beginning of period	826	1,485
Cash and cash equivalents at end of period	394	688
Guarantor Subsidiaries [Member] \| Reportable Legal Entities [Member]
Condensed Cash Flow Statements Captions [Line Items]
CASH PROVIDED BY (USED IN) OPERATING ACTIVITIES	3,595	1,631
INVESTING ACTIVITIES
Capital expenditures	(3,007)	(2,337)
Proceeds from asset dispositions and other	9	83
Cash used in investing activities	(2,998)	(2,254)
FINANCING ACTIVITIES
Net transfers from (to) Parent	(853)	350
Intercompany dividends	398	113
Principal payments on debt	(62)	(29)
Other, net		128
Cash provided by (used in) financing activities	(517)	562
Effect of exchange rate changes on cash	(2)	(9)
Net decrease in cash and cash equivalents	78	(70)
Cash and cash equivalents at beginning of period	158	257
Cash and cash equivalents at end of period	236	187
Non-guarantor Subsidiaries [Member] \| Reportable Legal Entities [Member]
Condensed Cash Flow Statements Captions [Line Items]
CASH PROVIDED BY (USED IN) OPERATING ACTIVITIES	201	333
INVESTING ACTIVITIES
Capital expenditures	(257)	(295)
Proceeds from asset dispositions and other	7	15
Cash used in investing activities	(250)	(280)
FINANCING ACTIVITIES
Net transfers from (to) Parent	153	(6)
Payment on loan between subsidiaries	326
Intercompany dividends	(398)	(113)
Principal payments on debt	(3)	(6)
Other, net	(1)	(127)
Cash provided by (used in) financing activities	77	(252)
Effect of exchange rate changes on cash	1	(29)
Net decrease in cash and cash equivalents	29	(228)
Cash and cash equivalents at beginning of period	1,381	1,538
Cash and cash equivalents at end of period	$ 1,410	$ 1,310

The net cash inflow (outflow) from parent as a source of financing.

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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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